Pyridinium compounds



Patented June 27, 1950 UNITED STATES PATENT OFFICE 2,512,789 PYRIDINIUMCOMPOUNDS Francis E. Oislak and Leslie H. Sutherland, Indianapolis, Ind.

No Drawing. Application October 24, 1946, Serial No. 705,482

8 Claims. (01. 260-290) This invention relates to a new class ofchemical compounds and to the process of making them. More particularlyit relates to the class of chemical compounds formed by reacting avinylpyridine with a pyridine salt, which com pounds may be representedby the following general formula:

In this formula the group represents hydrogen, a benzo, or a substitutedbenzo radical; Y and Y represent hydrogen, an alkyl, or a substitutedalkyl radical; X represents an anion.

In general, the compounds of this invention may be prepared by reactinga vinylpyridine, or a compound which upon dehydration is converted intoa vinylp-yridine, with a pyridine salt. The reaction is advantageouslycarried out in a solvent, although it is not necessary to use a solvent.

By the term pyridine salt we mean a compound formed by interaction of apyridine and an inorganic acid and having the general formula:

in which the group represents hydrogen, a benzo, or a, substituted benzoradical; Y represents hydrogen, an alkyl, or a substituted alkylradical; X represents an anion.

By the term benzo we mean the divalent radical C4H4=.

Our invention is described more fully in the following specific examplesof forming the new compounds therein set forth. It should be understood,however, that these examples are given by way of illustration only andthat our invention is not to be limited to the details set forththerein. The parts are by weight.

2 EXAMPLE 1 2 -pyridylcthylpyridinium chloride ong-on/ A A solution of29 parts of pyridine hydrochloride in 20 to 30 parts of pyridine isprepared in any convenient manner. While stirring the pyridinehydrochloride solution, 26 parts of 2-vinylpyridine is slowly added toit. A reaction occurs most immediately, heat is evolved, and thetemperature of the mixture rises. After all the 2- vinylpyridine'hasbeen added, the stirring is continued for from about minutes to about. 1hour. Then the mixture is cooled to about 15 C. to 0. Upon such coolingZ-pyridylethyler liquor in any convenient manner.

EXAMPLE 2 Z-pyridylethylpyridinium thiocyanate N oHl-cH'l I A solutionof 36 parts of thiocyanic acid in parts of pyridine is prepared in anyconvenient manner. While stirring the pyridine solution of thiocyanic.acid, 55 parts of -vinylpyridine is slowly added to it. After all the2-vinylpyridine has been added, the stirring is continued for about 1 to2 hours longer. The mixture is then allowed to stand at room temperatureovernight. During such standing, crystals of 2-pyridylethylpyridiniumthiocyanate crystallize-from the solution; these crystals are separatedfrom the moth- The 2-' 3 pyridylethylpyridinium thiocyanate thusobtained is fairly pure and can be used as such for many purposes, ifhowever a greater purity is desired the above obtained product isrecrystallized from any suitable solvent, as from acetone,

The purified 2-pyridylethylpyridinium thiocyanate melts .at about 115C-.; it is freely soluble in water, but is not soluble in hydrocarbonsolvents.

One convenient manner of preparing the solu tion of thiocyanic acid inpyridine is as follows: Fifty parts of finely ground sodium thiocyanateare dispersed in 140 parts of pyridine; to this dispersion is added 18parts of anhydrous hydrogen chloride, the dispersion is stirred duringthe addition of the hydrogen chloride and for about 15 minutes after allof the hydrogen chloride has been added; the hydrogen chloride reactswith the sodium thiocyanate to form sodium chloride, which precipitatesfrom the solution, and thincyanic acid, which dissolves in the pyridine;the sodium chloride is separated from the solution by filtration.

EXAMPLE -3 6-methyl-Z-ioyridylethyl-sl'-methylpyridinium chloride 7 NACHrCH/ pyridylethyll-methylpyridinium chloride crystallizes from thesolution. The crystals are separated from the mother liquorbyfiltration. They are further purified by recrystallization fromnbutanol. The 6-methyl 2 pyridylethyl-4'-inethylpyridinium chloridemelts at about 210 C.

EXAMPLE 4 z-pyn'clylethylpyridz'nium sulfate While vigorously stirring400 parts of pyridine add to it 50 parts of concentrated sulfuric acid.A reaction occurs forming a suspension of finely divided pyridinesulfate in the pyridine and bringing about a rise in temperature of themixture. 'The mixture is cooled to about 30 C. to 40 C. and Whilestirring it, 50 parts of 2-viny1pyridine is slowly added to it. Areaction occurs almost immediately, as evidenced by the precipitation ofcrystals of 2-pyridylethylpyridinium sulfate. After all of the2vinylpyridine has been added "the mixture is stirred for about one hourlonger, then it is cooled to room temperature. The crystals ofZ-pyridylethylpyridinium sulfate are separated, as by filtration; theyare purified by recrystallization from ethyl alcohol. The so purified2-pyridylethylpyridinium sulfate melts at about 169 C.

EXAMPLE 5 4-pyridyZethyl-4-n-amylpyridinium chloride CHz-CH: 01 O \qfi NQ A solution of 93 parts of 4-n-amylpyridine hydrochloride in 70 toparts of 4-n-amylpyridine is prepared in any convenient manner. Whilestirring the 4-n-amylpyridine hydrochloride solution, 52 parts of4-viny1pyridine is slowly added to it. A reaction occurs almostimmediately, a precipitate is formed. After all of the 4-vinylpyridinehas been added, the stirring is continued for about 30 to 60 minutes.Then the mixture is cooled to room temperature and the precipitate,which is -pyridylethyli-n-amylpyridinium chloride, is separated from themother liquor, as by filtration. The 4 pyridylethyl-4'-n-amylpyridiniumchloride is washed with benzene to remove any adhering mother liquor,and is then dried. The 4-pyridylethyl-4-n-amylpyridinium chloride thusobtained melts at about 242 C.

A mixture of 82 parts of isoquinoline hydrochloride (4,5-benzopyridinehydrochloride) and 60 to 80 parts of isoquinoline is prepared in anyconvenient manner; one convenient way of preparing such a mixture is tomix 50 parts of aqueous (36%) hydrochloric acid with 124 to 144 parts ofisoquinoline and then remove the water (which was introduced with thehydrochloric acid) by distillation. Them-ixture of isoquinolinehydrochloride is liquified by heating it to about C. to C.; whilemaintaining it in liquid form and while stirring it, 67 parts of 2-vinyl-5-ethylpyridine is slowly added to it. After all the2-vinyl-5-ethyl-pyridine has been added, the stirring is continued "forabout 30 minutes. The mixture is then cooled to room temperature. The5-ethyl-Z-pyridyl'ethylpyridinium chloride, which crystallizes from thesolution upon such cooling, is separated from the mother liquor byfiltration. The crude product thus obtained is purified byrecrystallization from butyl alcohol. The thus purified5-ethyl-2-pyridylethylisoquinoliniu'm chloride melts at about C.

Z-pyridylethyl-4'-propanolpyridinium sulfate LN Queen/g Sixty-nine partsof 4- propanolpyridine are dissolved in 400 parts of methanol. Thissolution is cooled to about C. and while being maintained at thistemperature, 48 parts of concentrated sulfuric acid are slowly added.Then 52 parts of 2-vinylpyridine are added and the mixture stirred forabout 2 hours. Now most of the methanol, about 350 parts, is removed byvacuum distillation, and the residue is cooled to below 0 0. Upon suchcooling 2-pyridylethy1-4-propanolpyridinium sulfate crystallizes out.(At times it is difficult to start th crystallization, and it isnecessary to seed the cooled solution to cause crystallization.)4-propanolpyridinium sulfate are separated from the mother liquor in anyconvenient manner, as by filtration. The thus recovered crystals arerecrystallized from a solvent consisting of about three parts of acetoneand one part of methanol. The so purified 2-pyridylethyl-4'-propanolpyridinium sulfate melts at about 117 C.

EXAMPLE 8 2myridylethylpyridinium sulfate Seventy-five parts of pyridineis mixed with 10.5 parts of concentrated sulfuric acid. To this mixtureis added 13.5 parts of Z-ethanolpyridine (a compound which upondehydration is converted into a vinylpyridine) the resulting mixture isheated under reflux conditions for about 4 hours. During the refluxingperiod, 2-pyridylethylpyridinium sulfate separates as an oil. After therefluxing, the mixture is allowed to settle, whereupon two layers areformed. The lower layer, which is the 2-pyridylethylpyridinium sulfateis separated by decantation. The small amount of water and pyridine thatis contained in the thus separated 2-pyridylethylpyridinium sulfate isremoved by evaporation in vacuo. The dried z-pyridylethylpyridiniumsulfate is recrystallized from ethyl alcohol.

We believe the formulae used to represent the compounds formed inaccordance with our invention correctly portray their molecularstructure. We however are not to bebound by the molecular configurationof these compounds.

The compounds of this invention are useful as fungicides and in organicsyntheses.

We claim as our invention:

1. Pyridylethylpyridinium compounds of the class consisting of a2-pyridylethylpyridinium and a l-pyridylethylpyridinium compound havingthe following general formula:

N N carom in which the group represents one of the group consisting ofhydrogen and a benzo radical; Y and Y represent one of the groupconsisting of hydrogen and an alkyl radical; and X represents an anion.

2. Pyridylethyl yridinium compounds of the The crystals ofz-pyridylethyb' class consisting of a Z-pyridylethylpyridinium and a4-pyridylethylpyridinium compound having the following general formula:

in which the group Z represents one of the group consisting of hydrogenand a benzo radical; Y and Y represent one of the group consisting ofhydrogen and an alkyl radical; and X represents an anion. g

4. A new compound having the following general formula:

in which the group represents one of the group consisting of hydrogenand a benzo radical; Y and Y represent one of the grou consisting ofhydrogen and an alkyl radical; and X represents an anion.

5. The process of reacting a pyridine salt of an inorganic acid with acompound of the class consisting of a 2-vinylpyridine and al-vinylpyridine and a compound which upon dehydration is converted intoa compound of the class consisting of a 2-vinylpyridine and a4-vinylpyridine.

6. The process of reacting a compound of the [classconsisting of a2-vinylpyridine and a el-vinylpyridine with a pyridine salt of aninorganic acid.

'7. The process of reacting a 2-vinylpyridine with a pyridine salt of aninorganic acid.

8. The process of reacting a 4-vinylpyridine with a pyridine salt of aninorganic acid.

FRANCIS E. CISLAK. LESLIE H. SUTHERLAND.

REFERENCES CITED 65 The following references are of record in th file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,272,159 Cislak Feb. 3, 19422,300,741 Cislak Nov. 3, 1942 2,338,571 Cislak Jan. 4, 1944 OTHERREFERENCES Sedgwick: Organic Chemistry of Nitrogen, p. 531 (1937),Oxford Press,

Certificate of Correction Patent No. 2,512,789 June 27, 1950 FRANCIS E.OISLAK ET AL.

It is hereby certified that errors appear in the above numbered patentrequiring correction as follows:

In the grant, lines 1 and 13, name of co-inventor, for Frank E. Oislakread Francis E. Cislalc;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Ofiice.

Signed and sealed this 26th day of September, A. D. 1950.

THOMAS F. MURPHY,

Assistant OomMissz' ner of Patents.

1. PYRIDYLETHLPYRIDINIUM COMPOUNDS OF THE CLASS CONSISTING OF A 2-PYRIDYLETHYLPYRIDINIUM AND A 4-PYRIDYLETHYLPYRIDINIUM COMPOUND HAVING THE FOLLOWING GENERAL FORMULA: 